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http://dx.doi.org/10.9720/kseg.2012.3.343

Analysis of Slope Stability Considering the Saturation Depth Ratio by Rainfall Infiltration in Unsaturated Soil  

Chae, Byung-Gon (Geologic Environment Research Division, Korea Institute of Geoscience and Mineral Resources)
Park, Kyu-Bo (Dept. of Geoinformation Engineering, Sejong University)
Park, Hyuck-Jin (Dept. of Geoinformation Engineering, Sejong University)
Choi, Jung-Hae (Geologic Environment Research Division, Korea Institute of Geoscience and Mineral Resources)
Kim, Man-Il (Water Resources Business Division, Korea Water Resources Corporation)
Publication Information
The Journal of Engineering Geology / v.22, no.3, 2012 , pp. 343-351 More about this Journal
Abstract
This study proposes a modified equation to calculate the factor of safety for an infinite slope considering the saturation depth ratio as a new variable calculated from rainfall infiltration into unsaturated soil. For the proposed equation, this study introduces the concepts of the saturation depth ratio and subsurface flow depth. Analysis of the factor of safety for an infinite slope is conducted by the sequential calculation of the effective upslope contributing area, subsurface flow depth, and the saturation depth ratio based on quasi-dynamic wetness index theory. The calculation process makes it possible to understand changes in the factor of safety and the infiltration behavior of individual rainfall events. This study analyzes stability changes in an infinite slope, considering the saturation depth ratio of soil, based on the proposed equation and the results of soil column tests performed by Park et al. (2011 a). The analysis results show that changes in the factor of safety are dependent on the saturation depth ratio, which reflects the rainfall infiltration into unsaturated weathered gneiss soil. Under continuous rainfall with intensities of 20 and 50 mm/h, the time taken for the factor of safety to decrease to less than 1.3 was 2.86-5.38 hours and 1.34-2.92 hours, respectively; in the case of repeated rainfall events, the time taken was between 3.27 and 5.61 hours. The results demonstrate that it is possible to understand changes in the factor of safety for an infinite slope dependent on the saturation depth ratio.
Keywords
Equation of the factor of safety for an infinite slope; Rainfall infiltration; Saturation depth ratio; Weathered gneiss soil; Landslide prediction;
Citations & Related Records
Times Cited By KSCI : 4  (Citation Analysis)
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